Manipulating models and grasping the ideas they represent

This article notes the convergence of recent thinking in neuroscience and grounded cognition regarding the way we understand mental representation and recollection: ideas are dynamic and multi-modal, actively created at the point of recall. Also, neurophysiologically, re-entrant signalling among cortical circuits allows non-conscious processing to support our deliberative thoughts and actions. The qualitative research we describe examines the exchanges occurring during semi-structured interviews with 360 children age 3–13, including 294 from New Zealand (158 boys, 136 girls) and 66 from China (34 boys, 32 girls) concerning their understanding of the shape and motion of the Earth, Sun and Moon (ESM). We look closely at the relationships between what is revealed as children manipulate their own play-dough models and their apparent understandings of ESM concepts. In particular, we focus on the switching taking place between what is said, what is drawn and what is modelled. The evidence is supportive of Edelman’s view that memory is non-representational and that concepts are the outcome of perceptual mappings, a view which is also in accord with Barsalou’s notion that concepts are simulators or skills which operate consistently across several modalities. Quantitative data indicate that the dynamic structure of memory/concept creation is similar in both genders and common to the cultures/ethnicities compared (New Zealand European and Māori; Chinese Han) and that repeated interviews in this longitudinal research lead to more advanced modelling skills and/or more advanced shape and motion concepts, the results supporting hypotheses (Kolmogorov–Smirnov alpha levels.05; rs: p < .001)

Ausubel's meaningful learning re-visited

This review provides a critique of David Ausubel’s theory of meaningful learning and the use of advance organizers in teaching. It takes into account the developments in cognition and neuroscience which have taken place in the 50 or so years since he advanced his ideas, developments which challenge our understanding of cognitive structure and the recall of prior learning. These include (i) how effective questioning to ascertain previous knowledge necessitates in-depth Socratic dialogue; (ii) how many findings in cognition and neuroscience indicate that memory may be non-representational, thereby affecting our interpretation of student recollections; (iii) the now recognised dynamism of memory; (iv) usefully regarding concepts as abilities or simulators and skills; (v) acknowledging conscious and unconscious memory and imagery; (vi) how conceptual change involves conceptual coexistence and revision; (vii) noting linguistic and neural pathways as a result of experience and neural selection; and (viii) recommending that wider concepts of scaffolding should be adopted, particularly given the increasing focus on collaborative learning in a technological world

Pulsations, eruptions, and evolution of four yellow hypergiants

We aim to explore the variable photometric and stellar properties of four yellow hypergiants (YHGs), HR8752, HR 5171A, $\rho$ Cas, and HD 179821, and their pulsations of hundreds of days, and long-term variations (LTVs) of years. We tackled multi-colour and visual photometric data sets, looked for photometric indications betraying eruptions or enhanced mass-loss episodes, calculated stellar properties mainly using a published temperature calibration, and investigated the nature of LTVs and their influence on quasi-periods and stellar properties. The $BV$ photometry revealed a high-opacity layer in the atmospheres. When the temperature rises the mass loss increases as well, consequently, as the density of the high-opacity layer. As a result, the absorption in $B$ and $V$ grow. The absorption in $B$, presumably of the order of one to a few 0\fm1, is always higher than in $V$. This difference renders redder and variable $(B-V)$ colour indexes, but the absorption law is unknown. This property of YHGs is unpredictable and explains why spectroscopic temperatures are always higher than photometric ones. We propose shorter distances for $\rho$ Cas and HR 5171A than the accepted ones. Therefore, a correction to decrease the blue luminescence of HR 5171A by polycyclic aromatic hydrocarbon (PAH) molecules is necessary, and HR 5171A would no longer be a member of the cluster Gum48d. HR 5171A is only subject to one source of light variation, not by two as the literature suggests. Eruptive episodes of YHGs prefer relatively cool circumstances when a red evolutionary loop (RL) has shifted the star to the red on the HR diagram. After the eruption, a blue loop evolution (BL) is triggered lasting one to a few decades. The reddening episode of HR 5171A between 1960 and 1974 was most likely due to a red loop evolution, and the reddening after the 1975 eruption was likely due to a shell ejection.Comment: 28 pages, 18 figures, Accepted for Astronomy and Astrophysic

The novice-expert continuum in astronomy knowledge

The nature of expertise in astronomy was investigated across a broad spectrum of ages and experience in China and New Zealand. Five hypotheses (capable of quantification and statistical analysis) were used to probe types of expertise identified by previous researchers: (a) domain-specific knowledge-skill in the use of scientific vocabulary and language and recognising relationships between concepts in linguistic and schematic forms; (b) higher-order theory in terms of conceptual structure and enriched scientific knowledge and reasoning; with an expectation of cultural similarity. There were 993 participants in all, age 3–80 years, including 68 junior school pupils; 68 pre-school pupils; 112 middle-school students; 109 high-school students; 79 physics undergraduates; 60 parents; 136 pre-service primary teachers; 131 pre-service secondary teachers; 72 primary teachers; 78 secondary teachers; 50 amateur astronomers and astronomy educators; and 30 astronomers and physicists; with approximately equal numbers of each group in both cultures; and of boys and girls in the case of children. For them, the methodology utilised Piagetian interviews with three media (verbal language, drawing, play-dough modelling), and for adults a questionnaire inviting responses in writing and drawing was used. The data from each group were categorised into ordinal scales and then analysed by means of Kolmogorov–Smirnov two-sample tests. The findings supported the hypotheses with evidence of all forms of expertise increasing with experience in both cultures (α level 0.05). The relative gains, overlaps and deficits in expertise across the novice-expert continuum are explored in detail

Gender effects in children's development and education

This paper attempts to clarify several lines of research on gender in development and education, inter-relating findings from studies on intuitive/informal knowledge with those from research on achievements and attitudes in science. It acknowledges the declining proportions of male teachers world-wide and examination successes which indicate a reversal of educational disadvantage from female to male; as well as the recent evidence on the effects of the gender of teachers upon student success. An empirical contribution to the literature is offered, drawing from the gender-related findings from research on children's cosmologies in China and New Zealand with 346 boys and 340 girls (of whom 119 boys and 121 girls participated in the current study). The investigation focused on children's concepts of the motion and shape of the Earth through observational astronomy and gave children opportunities to express their ideas in several modalities. The in-depth interviews allowed children to share their meanings with gender differences becoming apparent (e.g. girls' superior ability to visually represent their cosmologies and boys' greater awareness of gravity). However, these differences were not universal across genders or cultures and marked similarities were apparent both in the content of children's responses and in their reasoning processes. By comparing boy/girl cosmological concept categories and by tracking their developmental trends by age, statistical evidence revealed the extent of the similarities within and across these diverse cultures. The findings reinforce those from the authors' knowledge restructuring and cultural mediation studies and provide support for the view that boys and girls have similar, holistic-rather-than-fragmented, cosmologies which have features in common across cultures and ethnic groups